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Capturing resting T cells: the perils of PLL.

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Santos, Ana Mafalda 
Ponjavic, Aleks 
Fritzsche, Marco 
Fernandes, Ricardo A 
de la Serna, Jorge Bernardino 


To the editor — Full understanding of lymphocyte activation will require thorough characterization of the ‘resting’ state and how it changes. Surfaces coated with the cationic homopolymer poly-L-lysine (PLL) are widely used for total internal reflection fluorescence (TIRF) imaging of the organization of surface proteins on resting lymphocytes^1,2,3,4,5 because PLL is assumed to be inert. Here we found that PLL initiated T cell signaling and profoundly altered the activity of membrane proteins such as the T cell antigen receptor (TCR). Therefore, the emerging idea that receptors and signaling proteins cluster by default^1,2,3,4,5, which has been based mostly on studies of lymphocytes interacting with PLL-coated surfaces, needs reconsideration.



Calcium Signaling, Cell Line, Cells, Cultured, Humans, Jurkat Cells, Polylysine, T-Lymphocytes

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Nature Immunology

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Springer Nature
Engineering and Physical Sciences Research Council (EP/L027631/1)
Wellcome Trust (via University of Oxford) (207547/Z/17/Z)
Supported by a Royal Society University Research Fellowship (UF120277 to S.F.L.) and Research Professorship (RP150066 to D.K.); the EPSRC (EP/L027631/1 to A.P.,); the Wellcome Trust (098274/Z/12/Z to S.J.D., and WT101609MA to R.A.F.); PA Cephalosporin Fund (C.E.); the Wolfson Imaging Centre Oxford (funded by the Wolfson Foundation and Wellcome Trust; 104924/14/Z/14); the Micron Advanced BioImaging Unit (Wellcome Trust Strategic Award 091911); the Medical Research Council (MC_UU_12010/Unit Programmes G0902418 and MC_UU_12025); an MRC/BBSRC/EPSRC award (MR/K01577X/1); and a Marie Skłodowska-Curie Intra-European grant (707348 to I.U.).